The object of the present invention is a process for the visual display of channel signals supplied by a classification sonar from objects lying on the sea bed. This process make possible a presentation of the channel signals which makes it possible to produce an improved classification relative to the prior art.
A sonar of the classification type is designed for identifying and recognizing objects lying on the sea bed from the shape of the shadow they project. This type of sonar transmits acoustic wave pulses in directions which are inclined relative to the sea bed. On receipt, angular bearing channels are formed. The shadow effect of an object lying on the sea bed suppresses the echo signal coming from the bed. It is from this shadow that the shape and dimensions of the object are identified.
In the display devices of the prior art, presentation is made according to a nominally polar coordinate representation .rho., .theta. where .rho. is the range of the object and .theta. the bearing angle. The cathode ray tube scan along the horizontal axis is nominally proportional to .theta., and that along the vertical axis is nominally proportional to .theta..
This representation in .rho., .theta. is distorted relative to that which an observer placed at the sonar location would see, and this makes classification difficult.